I would like to define a math operator that looks a bit like this, which I mocked up in an image editor from the
Sometimes there will be a different letter than lambda inside the box, or an expression like
\lambda', but the box should always be the same size, and always be square - it's meant to be an inline operator with a symbol drawn on it, not a box around part of a formula.
I don't mind if I have to manually position the formula inside it, as there will probably only be a few different letters that I'll use.
It doesn't have to be based on
\square. In fact I think it would look nicer if the baseline was a bit lower, to match
+ for example.
Is there a reasonable way to achieve this?